Earlier this month, the National Highway Traffic Safety Administration proposed a new rule requiring automakers to install event data recorders, known as EDRs or black boxes, in all light passenger vehicles. While the rule would expand the number of vehicles equipped to record critical information in the moments preceding a crash, that alone won’t aid investigations of traffic deaths or strengthen cases against reckless drivers. For black boxes to help get to the bottom of pedestrian and cyclist fatalities, changes to local crash investigation procedures and to EDR technology itself need to happen as well.
Clara Heyworth was killed by a driver whose black box data was wiped away before police thought to look for it. Photo via New York Times
Most cars already have black boxes. They’ve been around since 1996, and NHTSA says about 96 percent of 2013 models have them. The agency wants to make that 100 percent, starting in September 2014.
Black boxes on airplanes get more press than those in cars, since they’ve helped piece together the factors behind some high-profile plane crashes. In cars, event data recorders can tell you how fast the vehicle was going, whether the brake was activated, the force of the crash, the state of the engine throttle, when the airbag deployed, and whether a vehicle occupant’s seatbelt was buckled.
All good information. But black boxes don’t always work if it was a pedestrian or a cyclist who was struck.
Event data recorders are part of the airbag safety system. They’re what tells the airbags to deploy. And if the crash isn’t forceful enough to trigger the airbags, the EDR doesn’t record the data.
James Harris of Harris Technical Services, which provides expert reconstruction of traffic crashes, says black boxes “have been known to” record crashes with pedestrians, but “it’s not absolute.”
Sensors mounted around the edge of the car might detect a person there, but if the crash isn’t forceful enough to set off an airbag deployment, the black box probably won’t record it.
“If their body makes contact with the front of the car near one of the forward sensors – ah! Now you might have a record started,” Harris told Streetsblog. “They’re not designed for that necessarily. What we’re looking at are forces.”
It’s yet another vulnerability that comes with being a “vulnerable street user.” Flesh and bone — or even a bike frame — often won’t cause a severe enough impact to register with the black box. Harris said a bigger, heavier vehicle, like a Lincoln Continental, while being more likely to cause damage, is actually less likely to record a crash with a pedestrian or cyclist because of its greater mass relative to the victim. Meanwhile, the NHTSA rule doesn’t encompass heavy trucks or buses, which aren’t required to have black boxes installed.
When it comes to using black box data in crash investigations and reckless driving prosecutions, much needs to happen at the local and state level before the technology is consistently applied to hold dangerous drivers accountable. In cases where EDRs do record a crash involving a bicyclist or pedestrian, police and district attorneys rarely use the information.